Resource consumption calculator

ABSTRACT

A process tool controller of a semiconductor processing tool is provided with software that enables collecting, monitoring and logging information regarding the tool&#39;s consumption. Data is collected from the devices used for control of process conditions via the analog and digital inputs and outputs of the process tool controller. Consequently, the devices for controlling the process conditions have the additional function of measuring the tool&#39;s consumption. In this way the information regarding the tool&#39;s consumption is completely collected on board of the process tool. The parameters to be monitored and reported can be configured by the user, with use of a configuration editor, resulting in optimum flexibility of the system. In the illustrated embodiment, the user interface of the consumption monitoring and logging software is integrated into the user interface of the process control and monitoring software. The information regarding the tool&#39;s consumption can be communicated to a supervisor computer via a network.

REFERENCE TO RELATED APPLICATION

[0001] This application claims the priority benefit under 35 U.S.C.§119(e) of provisional Application No. 60/272,393, filed Feb. 28, 2001.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The invention relates to a control, data monitoring and loggingsystem for a process tool.

[0004] 2. Description of the Related Art

[0005] A process tool executes a treatment according to predeterminedconditions on material to be treated. Examples are process tools for thetreatment of semiconductor wafers, chemical reactors etc. A process tooltypically comprises a number of devices like valves, mass flowcontrollers, a temperature controller providing input signals to aThyristor Pack or Silicon Controlled Rectifier (SCR), empowering aheating element to be able to control the processing conditions like gasflows, pressure, temperature, etc. A process tool controller controlsthese devices. For this purpose the controller comprises a number ofdigital inputs and outputs and a number of analog inputs and outputs.Via the outputs, the various devices are controlled, and via the inputs,information is collected about the actual conditions in the processtool.

[0006] In general, process tools have a significant environmental impactbecause they consume significant amounts of gases, power, cooling water,air extraction, materials etc. For a processing plant it is important toknow the total consumption of the plant in order to be able to guaranteea sufficient supply of the utilities. Furthermore, information about thetime-average usage of the utilities is important from a cost point ofview. And, last but not least, legal regulations increasingly requirethat the environmental impact of a processing plant be known.

[0007] As a first approximation, the time-average consumption ofutilities can be calculated based on the specifications of the varioustools and assumptions of utilization. However, the actual consumptioncan deviate substantially from the calculated consumption because eitherthe specification or the assumptions or both can deviate from the actualsituation. Therefore, in the art the consumption is measured andmonitored.

[0008] In the art, the central supply systems for the various utilitiesare provided with consumption measuring devices and with a monitoringand data logging system so that the consumption on the plant level isknown. However, this information is very general and does not providethe possibility of a more detailed analysis of where the utilities aregoing, which processing tool is consuming more than others, and where inthe plant the most important savings could be achieved. For thesepurposes, information about the consumption of all the individualprocessing tools would be required. This information can be obtainedaccording to the prior art by providing the utilities supply systemswith consumption measuring devices at each individual tap point andmonitoring and logging the consumption by a central monitoring and datalogging system. However, this would make the utilities supply systemsvery complicated. It is the object of the present invention to providemeans and a method to monitor and report the utility consumption foreach tool while omitting the disadvantages outlined above.

SUMMARY OF THE INVENTION

[0009] According to one aspect of the present invention, the processtool controller of a processing tool is provided with software thatenables collecting, monitoring and logging information regarding thetool's consumption. The data is collected from the devices used forcontrol of process conditions via the analog and digital inputs andoutputs of the process tool controller. Consequently, the devices forcontrolling the process conditions have the additional function ofmeasuring the tool's consumption. In this way the information regardingthe tool's consumption is completely collected on board the processtool.

[0010] According to another aspect of the invention, the parameters tobe monitored and reported can be configured by the user with use of aconfiguration editor, resulting in optimum flexibility of the system.According to a further aspect of the invention, the user interface ofthe consumption monitoring and logging software is integrated into theuser interface of the process control and monitoring software. Accordingto another aspect of the invention, the information regarding the tool'sconsumption can be communicated to a supervisor computer via a network.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The aforementioned and other aspects of the invention will beunderstood from the description below and the appended drawings. Thedrawings, which include screen prints from an implemented embodiment ofthe invention, are meant to illustrate and not to limit the invention.

[0012]FIG. 1 is a schematic diagram showing an example of a controllerhierarchy in a processing plant.

[0013]FIG. 2 shows the main screen of control software with a “GreenTool” overview button, in accordance with a preferred embodiment of theinvention.

[0014]FIG. 3 shows a Green Tool overview screen for the software of FIG.2.

[0015]FIG. 4 shows the route from the main screen to the Green Toolconfiguration editor for the software of FIG. 2.

[0016]FIG. 5 shows the first screen of the Green tool configurationeditor for the software of FIG. 2.

[0017]FIG. 6 shows the editing screen for the consumable “O2” for thesoftware of FIG. 2.

[0018]FIG. 7 shows the editing screen for the consumable “Power” for thesoftware of FIG. 2.

[0019]FIG. 8 shows the route from the main screen to the Green Tooldetailed report for the software of FIG. 2.

[0020]FIG. 9 shows the screen where the time span for the detailedreport is selected for the software of FIG. 2.

[0021]FIG. 10 shows the screen where the parameters to be reported areselected for the software of FIG. 2.

[0022]FIG. 11 shows a detailed report according to the parametersselected for the software of FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0023] The invention will now be described in further detail below.Environmental impact of human activities is the subject of increasinginterest these days. The notion that the earthly resources are finite isincreasingly penetrating society and industry. In a first step tocontrol and to reduce the environmental impact of human activities, itis important to quantify this impact and to monitor it. To stimulatethis trend, industry has adopted a “Green Tool” label for tools that areprovided with means to monitor and log the usage of consumables.

[0024] To control the conditions during semiconductor processing, aplurality of devices are present in the process tool for the control of,for example, process gas flow, purge gas flow, electrical powerconsumption, cooling water flow, air extraction etc. These devices areconnected to a process tool controller either directly or indirectly viaa sub-controller by means of digital inputs and outputs and analoginputs and outputs. A digital input reflects the state of a digitalswitch, such as a flow switch that is in an “on” state when the flow isabove a certain threshold and in an “off” state when the flow is belowthe threshold value. A digital output controls the switching, forexample, of a valve which is normally closed; the off value of thedigital output corresponds to the closed state of the valve and the onvalue of the digital output corresponds to the open state of the valve.An analog input reflects an actual value of an analog parameter, such asan analog signal from a gas concentration sensor. An analog outputreflects a requested setpoint for an analog parameter, such as for a gasflow or a temperature. These inputs and outputs are used to controlexecution of the process according to the required conditions by meansof the process control software.

[0025]FIG. 1 shows an example of a control structure. Process tools 10,20 and 30 are each provided with, respectively, process tool controllers11, 21, and 31. Each process tool may comprise sub-controllers throughwhich the individual control devices are connected to the process toolcontroller. For tool 10, these sub-controllers are indicated byreference numerals 12-18. The individual process tool controllers aretypically connected via a network to a supervisor system 40 or a hostcomputer system. In the network, additional workstations 50, 51 could beprovided for monitoring purposes or for editing process “recipes.” Aprocess recipe is the software defining the sequence of events and thevalue of the different process parameters according to which the processtool controller controls the individual process control devices.Preferably, each of the tool controllers, supervisors or work stationsis a PC-type computer, provided with a screen display and, for humancontrol purposes, with a keyboard, a touch screen, a lightpen or thelike. A printer can be connected to each computer.

[0026] In each tool a lot of information is already available forprocess control purposes. In the preferred embodiment, this informationis utilized to monitor and log the usage of consumables in the tool.Therefore, a process tool is provided with a computer program, residingin the working memory of the process tool controller, which programcollects information about the actual consumption via the inputs andoutputs of the process tool controller. According to a further aspect ofthe invention, the parameters to be monitored and reported can beconfigured by the user, with use of a “Green Tool” configuration editor,resulting in optimum flexibility of the system. In a preferredembodiment, the user interface of the Green Tool software for monitoringand reporting information about consumables is integrated in the userinterface of the process control and monitoring software. In analternative embodiment, these respective user interfaces are notintegrated.

[0027] The Green Tool software works as follows. First, the parametersto be monitored are defined and configured by the Green Toolconfiguration editor. During the operation of the tool, the value ofthese parameters is sampled at a high frequency, preferably at least asfrequently as about every 10 seconds, more preferably at least aboutonce every second, and these values are stored, preferably in ashort-term or volatile memory. At a low frequency, preferably no morefrequently than once about every 10 minutes and more preferably lessfrequently than or equal to about once per hour, the sum of thesesampled values is calculated and this sum value is stored, together witha time stamp, on the hard disc of the process control computer for anindefinite time. The high frequency sampling is reset, and the oldvalues of the high frequency sampling are not kept in storage anylonger. In this way a strong data reduction is achieved, whereas for thepurpose of monitoring and logging the consumption, there is practicallyno loss of relevant information. The low frequency sampling results onlyin the loss of time resolution of the historic data, but the value ofthe cumulative consumption is still accurate. Preferably, the lowfrequency summing reduces data storage needs by a factor of at least100, more preferably by a factor of over 1000; in the illustratedembodiment, storage needs are reduced by 3600 times. At the same time,the measurement technique is such that the sums reflect data taken witha much higher resolution.

[0028] An embodiment of the invention will be explained in furtherdetail with reference to the figures. FIG. 2 shows the main screen ofthe process control and monitoring software. In the center of thescreen, a graphical presentation is given of a tool 100 for theprocessing of semiconductor wafers. The wafers, stored in cassettes, aresupplied on an input/output station 102, behind which a cassettetransfer and storage area 103 is present. Area 104 represents the wafertransfer area, where wafers are transferred from the cassettes intowafer boats, and area 105 represents the processing area where thewafers are processed while residing in the wafer boats. The illustratedprocessing area 105 comprises two process reactors or process tubes, 110and 120. At both sides of the graphical representation are userinterfaces 201 and 202 for each of the process reactors 110 and 120,respectively. A “Green Tool” overview button is indicated by referencenumeral 130. Pressing this button 130 activates a time window screensimilar to the one shown in FIG. 9 but with the resolution sectiondisabled, as will be understood from the description below.

[0029] After defining the time window and pressing the OK button, theGreen Tool overview screen as shown in FIG. 3 is displayed. This screenshows the cumulative consumption for all the configured consumables, foreach process tube separately as well as for both tubes combined.Pressing the exit button takes the user back to the main screen of FIG.2.

[0030] From FIG. 2, when the Config button 140 is pressed, the screen asshown in FIG. 4 is displayed. From this screen, pressing the MSC button160 causes the column of buttons at the right side to appear, and whenthe Green Tool button 170 is pressed the Green Tool configuration editorscreen as shown by FIG. 5 is displayed. From this Green Toolconfiguration editor the parameters to be monitored can be configured.

[0031] Two examples of configured parameters are given in FIGS. 6 and 7.In FIG. 6 the consumable O2 is configured. It can be observed that twoO2 flows are combined into this O2 consumable. It is also possible toapply a correction factor, such as when one mass flow controller readsin Standard Liter per Minute (SLM) and the other in Standard CubicCentimeter per Minute (SCCM). Additionally, it is possible to set acondition during which the consumable resource should be monitored. Inthis example, the O2 low flow is only monitored when the Digital Output“O2-low” is ON. This eliminates errors due to small offsets of the massflow controller, which, when integrated over a long period of time, cangive rise to erroneous results. Although “AO” (analog output) isindicated in the leftmost column, the software of the present embodimentis configured such that “AO” indicates a combination of an analog outputand an analog input. Such a combination is used with a mass flowcontroller, where AO indicates the setpoint and the corresponding Al isthe actual value of the MFC fed back into the tool controller.

[0032] In FIG. 7 the example of “Power” is given. The heating elementsof the process tubes comprise six zones. The most important powerconsumption is due to the heating element. As compared to the heatingelement, the power consumption of other devices in the tool isinsignificant. Unfortunately, the power consumed by the element is notactually measured by the process controller. Instead of installing powermeters in the tool, which is one solution to generate information, thepreferred embodiment employs another solution. Signals that areavailable in the tool are the control signals of the temperaturecontroller, which control signals are fed into the Thyristor Pack orSilicon Controlled Rectifier (SCR) unit for controlling the powerapplied by the SCR unit to the heating element. These signals, rangingfrom 0 to 100%, are taken as inputs for monitoring the powerconsumption. From the design of the element it is known what 100% meansand a corresponding calibration factor is applied to each power zone.Although aging might occur during the life time of the element, and theactual power might drift away a little bit from the calibrated value,the above-described approach gives a very good approximation of thepower consumption without adding additional components to the system.

[0033] The possibilities of the configuration editor, to defineconsumables and conditions as represented by the screens, are limited.However, the possibilities for defining consumables are not limited tothe possibilities facilitated by the available screens. Theconfiguration editor generates an ASCII file with formulas in RPN(Reverse Polish Notation) format. The formula in this ASCII file may beedited using an ordinary text editor. In this way more complex formulascan be defined, such as dividing two analog parameters or multiplicationof two analog parameters, taking the square root of a parameter or othermathematical operations. Such more complex formulas would, of course,also be reflected in newly designed screens.

[0034] When the reporting button 150 is pressed in the main screen ofFIG. 2, the screen as presented in FIG. 8 is displayed. This route canbe followed when a report more detailed than the overview report isdesired. When the Green Tool button 180 is pressed in the screen of FIG.8, the report generator screens of FIGS. 9-11 are displayed.

[0035]FIG. 9 shows the screen where the time span and time resolutionfor the reporting can be set. As shown, a number of “quick select”options are provided with present time span and resolution, as well asindividual options to more precisely set the time period and resolutionof interest for a tailored report. In the screen shown in FIG. 10, theparameters or channels to be reported can be selected. “Availablechannels” represents the previously user-defined parameters that arebeing monitored by the software for resource consumption. The user canselect among these monitored channels (“selected channels”) for purposesof his desired report. In FIG. 10, ten channels are shown (if there aremore, the user can scroll down to view them) that have been previouslyuser-defined for monitoring, while the user has selected six of thesechannels for generating the report. FIG. 11 shows an example of adetailed Green Tool report, showing five intervals (selected resolutionis weekly) for these five selected channels.

[0036] Advantageously, the system described herein makes use of existingprocess control features in a semiconductor processing tool to obtaininformation on resource consumption. Thus, the system can be employed onexisting tools by simply installing new software, without the expenseand tool downtime of retrofitting tools with separate monitoringhardware. The system is furthermore highly flexible, allowing the userto configure the software to monitor consumption of various resourcesfor various process recipes.

[0037] Although this invention has been described on the basis ofpreferred embodiments, modifications of the invention are possiblewithin the spirit and scope of this disclosure. This application isintended to cover modifications, adaptations or variations of theinvention which make use of its general principles. Furthermore, theinvention was described in the context of semiconductor manufacturingprocesses, but those of skill in the art will recognize that it may beadapted for use in various industries; for example, adaptation and usein chemical production or the like is possible.

I claim:
 1. A system for monitoring consumption of utilities bysemiconductor fabrication processes, comprising: at least onesemiconductor process tool comprising a plurality of process-controldevices for controlling process conditions within the process tool; atleast one tool controller communicating with the plurality ofprocess-control devices according to a process recipe for treatingworkpieces within the process tool; and computer software residing in amemory of said tool controller, the computer software compiling andstoring data relating to the consumption of resources by the tool. 2.The system of claim 1, wherein the plurality of process-control devicesinclude at least one heating element and at least one mass flowcontroller.
 3. The system of claim 2, wherein the computer softwarecompiles and stores data relating to the power output to the at leastone heating element and gas flow through the at least one mass flowcontroller.
 4. The system of claim 1, wherein the computer softwarecalculates resource consumption from inputs originating from theprocess-control devices and fed back into the tool controller.
 5. Thesystem of claim 4, wherein the computer software further calculatesresource consumption from outputs from the tool controller to theprocess-control devices.
 6. The system of claim 1, wherein the computersoftware is configured to collect data reflecting resource consumptionfrom the plurality of devices at a high frequency and to sum the data ata low frequency.
 7. The system of claim 6, wherein data collected at thehigh frequency is stored in a short-term memory and data summed at thelow frequency is stored in a long-term memory.
 8. The system of claim 7,wherein data collected at the high frequency is collected at least asfrequently as about every 10 seconds, and data summed at the lowfrequency is summed no more frequently than about every 10 minutes. 9.The system of claim 8, wherein data collected at the high frequency iscollected at least as frequently at about every second, and data summedat the low frequency is summed no more frequently than about every hour.10. The system of claim 7, wherein a frequency ratio of data collectionto data summing is greater than about
 100. 11. The system of claim 7,wherein a frequency ratio of data collection to data summing is greaterthan about
 1000. 12. The system of claim 1, wherein the computersoftware comprises an editor configured to select user-definedparameters for monitoring.
 13. The system of claim 12, wherein theuser-defined parameters include parameters selected from the groupconsisting of process gas flows, purge gas flows, electrical powerconsumption, and cooling water flows.
 14. The system of claim 13,wherein the purge gas flows include a plurality of purge gas parametersat different parts of the semiconductor process tool.
 15. The system ofclaim 12, wherein the user-defined parameters are monitored byhigh-frequency sampling of parameter values reported to the process toolcontroller by the process-control devices.
 16. The system of claim 15,wherein a rate of the high-frequency sampling is user-controlled at theeditor.
 17. The system of claim 15, wherein the high-frequency samplingrate is at least as frequent as once every 10 seconds.
 18. The system ofclaim 15, wherein the high-frequency sampling is at least as frequent asevery second.
 19. The system of claim 16, wherein the high-frequencysampling is summed in a low-frequency summing of sampled parametervalue.
 20. The system of claim 19, wherein a rate of the low-frequencysumming is user-controlled at the editor.
 21. The system of claim 19,wherein the low-frequency summing is conducted at a frequency of no morethan once about every ten minutes.
 22. The system of claim 19, whereinthe low-frequency summing is conducted at a frequency of no more thanonce about every hour.
 23. The system of claim 12, wherein the computersoftware further comprises a report generator configured to generateresource consumption reports relating to user-selected ones of theuser-defined parameters.
 24. The system of claim 1, wherein the computersoftware comprises a report generator configured to generate resourceconsumption reports relating to user-selected ones of parameters beingmonitored for consumption of resources.
 25. The system of claim 24,wherein the report generator allows user selection of a report timespan.
 26. The system of claim 25, wherein the report generator allowuser selection of a report resolution.
 27. The system of claim 24,wherein the resource consumption reports contain summed parameter valuesand process recipe details.
 28. The system of claim 24, wherein theresource consumption reports contain summed parameter values.
 29. Thesystem of claim 1, wherein a user interface of the computer software isintegrated into a user interface of the tool controller.
 30. A method ofdetermining resource consumption on a semiconductor process tool, themethod comprising: monitoring electronic inputs and outputs controllinga semiconductor process recipe; and calculating resource consumptionfrom said inputs and outputs.
 31. The method of claim 30, wherein saidinputs and outputs include analog signals.
 32. The method of claim 31,wherein said inputs and outputs include digital signals.
 33. A methodfor automatically monitoring consumption of utilities in at least oneprocess tool with software connected to the process tool, comprising:conducting continual high-frequency sampling of data relating toconsumption of utilities from a plurality of devices comprising saidprocess tool and storing said data in short-term memory; at specifiedintervals, calculating sums of said data, storing said sums in long-termmemory, and erasing said data from short-term memory; and based on saidsums, generating reports relating to said utility consumption data inresponse to requests from a user
 34. The method of claim 33, furthercomprising allowing user specification of the intervals for calculatingsums.
 35. The method of claim 33, further comprising allowing userdefinition of parameters to monitor for sampling of data.
 36. The methodof claim 34, further comprising allowing user selection of theuser-defined parameters for generating the reports.
 37. The method ofclaim 36, further comprising allowing user selection of time periods andresolutions for generating the reports.